ABSTRACT

Human membrane cofactor protein (CD46), a transmembrane complement regulatory protein, is utilized by laboratory-adapted and vaccine strains of measles virus (MV) as a receptor for virus entry. Recent studies have suggested that wild-type MV does not recognize this receptor. CD46 normally serves for protecting autologous cells from complement-mediated lysis. By studying CD46 in human cells and expression of human CD46 in heterologous species, evidence is accumulating which suggests CD46 may also modulate immune cell functions. This concise review critically examines the possibility that interaction with CD46 may provoke host defense response detrimental to MV, and strong negative selection may prevent wild-type MV from interacting with CD46 in vivo.